1. Field of the Invention
The invention relates to an electrical socket for burn-in and other tests on electronic devices, and more particularly, to an electrical socket having multiple pressure members that are biased to urge electrical leads of an electronic device against conductive traces of a circuit carrying member.
2. Prior Art
Electronic devices are commonly subject to burn-in and other testing at the time of manufacture to assure that the devices are free of defects when delivered to a customer. Burn-in testing includes subjecting the devices to elevated temperatures in an oven, thereby stressing the devices in order to quickly simulate numerous operating cycles. The burn-in testing causes break down of inferior elements so as to reveal those devices that would be likely to fail before achieving a minimum acceptable service life.
Flat pack electronic devices have numerous leads that are relatively narrow in order to achieve small centerline spacing (0.4 mm and smaller). The leads are easily marred or nicked during testing, and such damage is unacceptable. To avoid this problem, testing may occur at distal ends of the leads which are then removed prior to final lead forming.
An electrical socket for mounting a flat pack electronic device during burn-in and other testing is disclosed in U.S. Pat. No. 5,161,984 (Taylor et al.). The socket includes a base with a central area for receiving the device and a recessed area over which the leads of the device extend. A flexible etched circuit member is placed on the base with contact pads on one end of conductive traces being supported in the recessed area. The other ends of the traces are terminated to a printed circuit board (PCB). Pressure members on the base apply a normal force to the leads and contact pads to establish an electrical engagement therebetween.
Typically during the burn-in testing, a plurality of sockets having electronic devices to be tested are mounted on a PCB, and a plurality of PCB's having the sockets thereon are inserted in layered relationship in an oven. Reducing the height of the socket and its area on the PCB would permit a greater density of sockets to be inserted in a given size oven, thereby increasing the rate at which electronic devices could be tested, and correspondingly increasing production.
The pressure members disclosed by Taylor et al. are pivotally attached to the base and are inclined upwardly and outwardly away from the central area. The inclination of the pressure members adds to the overall height of the socket, and the pressure members extend further outwardly during pivoting movement. It would be desirable to provide an electrical socket for burn-in testing of electronic devices which has a reduced height and covers a smaller area on a PCB compared with the known electrical sockets. It would also be desirable to provide a top-actuated, top-loaded socket for use with robotic equipment, and to provide a socket that is repairable without desoldering of any connections.